1. Field of the Invention
This invention relates to a plate heat exchanger, and more particularly to a plate heat exchanger of the so-called open type.
2. Description of the Prior Art
A plate heat exchanger comprises a pack of plate elements which are clamped face to face and form therebetween interspaces for the media to change heat with each other through the plate walls. These interspaces are isolated from each other by sealing strips which extend slightly internally of the outer periphery of each plate and surround the heat transfer surface thereof. Every sealing strip, when clamping the plates, is in sealing contact between the plates. At a pack of plates, every second interspace communicates with a supply of one of both the media while the remaining interspaces communicate with a supply of the other. Hence, at each interspace are provided an inlet and an outlet for the media.
The plate heat exchanger is classified into the closed type and open type. At the closed type plate heat exchanger, the most conventionally current type, a sealing strip surrounds an interspace between a pair of adjacent plates. A pack of plates form a series of closed chambers for each medium. On the other hand, at the open type plate heat exchanger, only every second interspace forms a closed chamber for one of the media by means of sealing strips or in another way, while the remaining interspaces for the other medium are open throughout or partially of the periphery of the interspace.
This invention relates to an open type plate heat exchanger. The well-known open type plate heat exchanger has chambers which are formed between a plurality of plates and are under conditions of allowing fluid to communicate with one another. These chambers collectively constitute a unit provided with an inlet and an outlet for one of the media, the unit being disposed within a container provided with an inlet and an outlet for the other. Hence, the other medium is freely accessible to the open interspaces between the plates from the space within the container.
Conventionally, this kind of heat exchanger, which has a number of plates inserted within the container and clamped face to face by means of bolts and nuts between the covering at the end of container and a thrust plate, is uneconomical due to need of enlarging the container in size to an extent of interference for clamping the plates, resulting in that the container occupies a surplus space for installation thereof. Furthermore, a number of confronting plates, when clamped at a single stroke from both end sides, are subjected to ununiform clamping stress, whereby the number of plates for use is limited to hinder improvement in the efficiency of the heat exchanger.